JP2578842B2 - Azimuth measuring method by optical azimuth measuring device and apparatus used for the azimuth measuring method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial Application Field) The present invention provides an optical azimuth measuring device using an optical gyroscope such as a ring laser gyroscope or an optical fiber gyroscope utilizing the Sagnac effect. The present invention relates to an azimuth measuring method for measuring an azimuth such as a direction, a direction, and an apparatus used in the azimuth measuring method.

(Prior Art) Recently, an optical azimuth measuring device using an optical gyroscope such as a ring laser gyroscope or an optical fiber gyroscope utilizing the Sagnac effect has been developed. Here, the Sagnac effect is an effect that a phase change amount of light generated when a closed optical loop is rotated is obtained according to the following equation.

Δθ = (8πNS / cλ) · Ω Here, N is the number of times the light goes around the closed optical loop, S is the area surrounding the closed optical loop, c is the light speed, λ is the wavelength of the light, and Ω is the rotation. The angular velocity, Δθ, is the phase difference between the clockwise and counterclockwise light in the closed loop optical path.

This optical gyroscope detects rotation about a sensing axis, and the sensing axis is an axis orthogonal to a plane (referred to as a gyroscope surface) formed by an optical loop of the optical gyroscope.

As shown in FIG. 1 (a), when the gyro unit 1 of the optical azimuth measuring device is set such that the rotation axis J of the earth E and the sensing axis K are at right angles, the gyro unit 1 rotates the earth E. Is not affected at all, but when the gyro unit 1 of the optical azimuth measuring device is set so that the rotation axis J and the sensing axis K are not at a right angle, for example, as shown in FIG. Gyro unit 1 of the optical azimuth measuring device in the state where the angle between sensing axis K and rotation axis J is α.
Is set, the angular velocity of the rotation of the earth E is Ω _E
Then, the angular velocity component Ω of the rotation of the earth E sensed by the gyro unit 1 of the optical azimuth measuring device is Ω = Ω _E · cos α.

Therefore, when the gyro unit 1 of the optical azimuth measuring device is rotated at a constant angular velocity as shown in FIGS. 1 (a) and 1 (b), the gyro unit 1 of the optical azimuth measuring device has an angular velocity Ω.
_When the gyro output at _E is V (Ω _E ), the gyro unit 1
Each time the motor makes one rotation, a sinusoidal waveform of one cycle V = V (Ω _E ) · cos
α · sint is output (see FIG. 1 (c)). Here, the symbol t is the time or the rotation angle of the gyro unit 1. At t = 0, Ω = 0. Therefore, the azimuth can be determined by the attitude of the gyro unit 1 of the optical azimuth measuring device. When the rotation speed of the gyro unit 1 is increased, the gyro output from the gyro unit 1 is output and the frequency of the sine waveform is increased.

Therefore, in the conventional optical azimuth measuring device, the azimuth is determined based on a sine wave obtained by continuously rotating the gyro unit 1 at a constant speed.

(Problems to be Solved by the Invention) However, a rotating object generally has a shaft shake, and the shaft shake generated when the gyro unit 1 is rotated gives an unnecessary error to the sine wave output. At this time, the gyro 1 senses a rotation component as a vector projection onto the sensing axis K of the rotation angular velocity given to the gyro 1 itself different from the earth rotation.

Here, assuming that the rotation speed of the gyro unit 1 is one rotation per second, and the rotation axis is inclined by 1 ″ during one rotation of the gyro unit 1, when the gyro unit 1 rotates one rotation, The rotational angular velocity ΔΩ that 1 senses about the sensing axis K is ΔΩ = 2π × sin 1 ″ = 3.046 × 10 ⁻⁵ (rad / sec) On the other hand, the rotational angular velocity Ω _E of the earth _E is Ω _E = 7.272 × 10 ^-5 (rad / sec).

Therefore, assuming that the rotation speed of the gyro unit 1 is one rotation per second, and the gyro unit 1 makes one rotation, the rotation shaft tilts by 1 ″.
The rotation angular velocity of about half of the rotation of the earth E is received by the shaft deviation. Since this shaft shake occurs irregularly, the gyro output obtained by rotating the gyro unit 1 largely deviates from the sine waveform. In order to obtain an axial accuracy that can ignore the influence of the axial deviation, a considerably high level of manufacturing technology is required.

Further, the fluctuation of the rotation speed of the gyro unit 1 is also a cause of the deterioration of the sine waveform, and the gyro output obtained by rotating the gyro unit 1 has an error component based on the fluctuation of the rotation speed and an error based on the fluctuation of the shaft shake. The components are intricately entangled and deviate from the sine waveform.

In addition, a cause of an error in the gyro output obtained by rotating the gyro unit 1 is zero point drift. This zero point drift occurs at a relatively low frequency, and conventionally, to avoid this zero point drift,
A band-pass filter having a band-pass characteristic centered on the frequency corresponding to the rotation speed of the gyro unit 1 is provided, and the gyro output is passed through the band-pass filter. To avoid this zero point drift, It is desirable that the bandpass filter has a narrow bandwidth and the center frequency is as high as possible. Therefore, it is preferable to set the rotation speed of the gyro unit 1 as high as possible. However, when the rotation speed of the gyro unit 1 is increased, the influence due to the shaft deviation becomes remarkable.

Further, even if the rotation of the gyro unit 1 can be ideally performed in a state where there is no shaft deviation, if there is an inclination between the rotation shaft 2 and the true gyro surface 3 of the gyro unit 1, When the azimuth is measured at a place other than the equator assuming that the rotating shaft 2 is in the vertical axis direction, the positive and negative amplitude values of the sine waveform are different, and the obtained gyro output is the true value of the rotating shaft 2 and the true gyro unit 1. There is a problem that it is also affected by the inclination with respect to the gyroscopic surface 3.

In order to reduce these error factors, it is necessary to use advanced manufacturing techniques. However, even if such advanced manufacturing techniques are used, it is difficult to completely eliminate these error factors.

In addition, in the optical azimuth measuring device, when the angle α of the sensing axis K with respect to the rotation axis J increases, that is, when the azimuth is measured at a high latitude, the amplitude value of the gyro output becomes very small, and the azimuth measurement is performed. Almost difficult.

(Objects of the Invention) The present invention has been made in view of the above circumstances, and has an azimuth measuring method using an optical azimuth measuring device capable of solving the above-described various disadvantages of a conventional optical azimuth measuring device. An object of the present invention is to provide an apparatus used for the azimuth measuring method.

Configuration of the Invention (Means for Solving the Problems) The feature of the azimuth measuring method by the optical azimuth measuring device according to the present invention is that the rotation angular velocity of the earth rotation sensed by the gyro part of the optical azimuth measuring device is substantially zero. The gyro surface is oriented so as to be stationary, the relationship between the gyro output at this stationary position and the stationary position with respect to the reference position is determined, and then the gyro unit is rotated by 180 ° from the stationary position and stationary, and the The relationship between the 180 ° rotation stop position of the gyro part and the gyro output at this 180 ° rotation stop position is obtained, this operation is repeated many times, and a linear approximation is made by obtaining many relation quantities obtained in this way, The azimuth is obtained from the rotation angle at which the output of the gyro part of this straight line becomes zero.

The features of the device used in the azimuth measuring method by the optical azimuth measuring device according to the present invention are: a rotation axis for rotating the gyro part, and a rotation for rotating the gyro part including the rotation axis in a plane orthogonal to the rotation axis. A spindle and a rotation axis that is coaxial with the rotation axis of the gyro part at a predetermined rotation position of the rotation spindle, and the gyro part is used to correct a decrease in gyro output due to an increase in latitude. The gyroscopic surface is rotated around the rotation support shaft so as to measure the azimuth so that the sensed rotation angular velocity of the rotation of the earth increases.

(Example) Hereinafter, an example of an azimuth measuring method using an optical azimuth measuring apparatus according to the present invention and an apparatus used in the azimuth measuring method will be described with reference to the drawings.

FIG. 2 shows a first embodiment of an azimuth measuring method by an optical azimuth measuring apparatus according to the present invention and an apparatus used for the azimuth measuring method, wherein 10 is a surface plate section and 11 is a gyro section. A motor 12 is fixed to the base plate 10. The motor 12 has a rotating shaft 13. The gyro part 11 is attached to the rotary shaft 13 and
Rotated around 13. Above the motor 12, an encoder plate 14 is fixed concentrically with the rotating shaft 13. Gyro part 11
An encoder reading unit 15 is provided below the. The encoder reading unit 15 is, for example, the gyro unit 11
It is assumed that the rotational position of the gyro surface 15 determined from the outer shape is read. An optical loop is formed in the gyro unit 11 so that the sensing axis K is orthogonal to the rotation axis 13. In addition,
In this embodiment, the encoder plate 14 is fixed and the encoder reading unit 15 is rotated.However, the encoder reading unit 15 is fixed to the surface plate unit 10, and the encoder plate 14 is attached to the gyro unit 11 for rotation. It is also possible to adopt a configuration in which it is performed.

When the rotating shaft 13 of the motor 12 is set to be in the vertical axis direction and the motor 12 is rotated, a sine waveform as a gyro output is obtained by a change in the direction of the gyro surface 17.
Therefore, first, the gyro unit 11 is slowly and continuously rotated once. The gyro output of the gyro unit 11 and the output of the encoder reading unit 15 at this time are sent to a signal processing circuit (not shown). When the gyro unit 11 is continuously rotated once, it is possible to roughly determine the east, west, north and south directions based on the sine waveform. Also, even if the gyro unit 11 is not continuously rotated once, if the measurement is performed by stopping the rotation of the gyro unit 11 at four points of 90 °, the gyro output at each rotation stationary position for each 90 ° is obtained. With this azimuth measuring method, the east-west north-south azimuth can be roughly determined.
Some optical gyroscopes have a high resolution of 0.01 ° / h.For example, even if a gyroscope with a resolution of 0.1 ° / h is used, the azimuth can be roughly estimated on the equator with an accuracy of about 23 ′. Can be decided. Here, the symbol h indicates time.

Next, the gyro 11 is fixed so that the sensing axis K of the gyro 11 is roughly in the east-west direction.
Here, the gyro surface 17 is oriented in the east-west direction because the point where the rate of change of the sine wave curve is the largest is near the zero point, and the change in the gyro output with respect to the angle shift is large. When the sensing axis K is oriented in the east-west direction, the rotational angular velocity Ω _E of the rotation of the earth E sensed by the gyro unit 11 is almost zero. At this time, the gyro unit 11
It is stationary in a state close to that shown in FIG. In this state, the scale of the encoder plate 14 and the gyro output from the gyro unit 11 are read. As the value of the gyro output of the gyro unit 11,
The average over a predetermined time is used.

Next, the gyro unit 11 is quickly rotated by 180 ° from the rest position by the motor 12 as a rotation angle. In addition,
The accuracy of the rotation angle may not be 180 ° as long as it is within the accuracy described later. During the rotation of the gyro unit 11, the gyro unit
Gyro output from 11 is interrupted. And
At the 180-degree rotation stationary position of the gyro unit 11, the encoder plate 1
Read the scale of 4 and the gyro output from the gyro unit 11.
As the value of the gyro output of the gyro unit 11, the value obtained by averaging the value at the same time as the time at the rotation stationary position 180 ° before is used.

Specifically, first, as shown in FIG. 3, the gyro unit 11
The output of the encoder plate 14 at the rotation stationary position where the gyro output becomes substantially zero is x, and the average value of the gyro outputs of the gyro unit 11 is y. Here, the output x is a count value from the reference line A. The reference line A may be considered as, for example, a position where the output of the encoder plate 14 is zero. Next, the gyro unit 11
Is rotated by 180 ° in the direction of arrow M, and the output of the encoder plate 14 at the rotation rest position where the rotation is stopped is x ′, and the average value of the gyro output of the gyro unit 11 is y ′. This gyro part 11
The difference Y = y'-y between the gyro outputs y and y ', and the average X = (x + x') / 2 of the outputs x and x 'of the encoder plate 14 are calculated by the signal processing circuit.

The meanings of the average value X and the difference Y will be described with reference to FIGS. 4 and 5. FIG. 4 shows an ideal sine wave,
The horizontal axis can be considered to be the read value of the encoder plate 14, the vertical axis can be considered to be the gyro output of the gyro unit 11, and θ represents the read value of the encoder plate 14 when the output of the gyro unit 11 becomes zero. In FIG. 4, the position at which the gyro unit 11 is stopped is indicated by a square so that the output of the gyro unit 11 becomes substantially zero by the above-described method. Here, the output of the encoder board 14 is x, and the output of the gyro is y. Further, the outputs at the positions where the rotation is stationary by approximately 180 ° are x 'and y', respectively. Here, when the above calculation is performed, X
Is θ + 90 °, the value of Y is zero (see black circles in FIG. 4), and when the value of X is not θ + 90 °, for example, when X> θ + 90 °, Y <0 (4th When X <θ + 90 °, Y> 0 (see white triangle in FIG. 4). The measured X and Y values are plotted as a graph as shown in FIG. In order to obtain the next values of X and Y, the above-described calculation may be performed by replacing the outputs x and y at the position where the gyro unit 11 is again stopped by about 180 ° with old data. When repeating this measurement a number of data X _i, Y _i is obtained. These data X _i and Y _i should be plotted on a substantially straight line. Therefore, a straight line approximation using the least squares method based on these data X _i and Y _i , and an intersection Z between the straight line T obtained by the least squares method and the X coordinate is obtained. That is, in this example, an accurate east or west bearing based on the reference line A can be determined. Whether the direction is east or west can be determined from the direction obtained roughly or from the inclination of the obtained straight line.

By the way, when a tangent at the zero point of the sine waveform is drawn, the error from the sine waveform at a position shifted by 1 ° from the zero point is only 0.005%. Even if it is shifted by 2 ° from the zero point, it is about 0.02%. Therefore, in consideration of the measurement accuracy of the roughly measured azimuth, it is sufficient to perform the rotation accuracy in the range of 180 ° ± 1 °.

If this rotation is performed with reference to the scale of the encoder plate 14, the gyro unit 11 can be easily stopped within the range. 180 around the scale of the rough direction
What is necessary is just to rotate quickly while reading the scale of the encoder plate 14 so that the gyro unit 11 is stationary within the range of ° ± 1 °. Therefore, by rotating the scale of the encoder plate 14 as a reference,
By stopping the gyro unit 11 at a location within a certain range, it is not necessary to use the data of a portion largely deviating from the vicinity of the sine wave straight line. If the rotation of 180 ° is ideally performed, the measurement will always be made at the same output point of the encoder plate 14, and it will be impossible to make the final azimuth measurement, but in this case 180 ° This is done by forcibly changing the value.

According to the azimuth measuring method and the signal processing method, the gyro unit 11 is hardly affected by the zero point drift of the gyro output. This is because the zero-point drift causes the sine waveform to drift in the vertical direction, but the gyro output of the gyro unit 11 is trapped in a certain direction from the first measurement to the n-th measurement, and the amount is large. Even if this happens, there is basically no influence of drift because the value of Y is the difference. However, a drift that occurs during one measurement appears as an error. However, this minimizes the time required for one measurement, that is, the time required for rotating the gyro unit 11 from standstill to the standstill and the time required for averaging the gyro output. Thus, the drift error caused by this one measurement can be avoided.

Here, the rotating shaft 13 is in the vertical axis direction, and the gyro unit 11
It is assumed that the true gyro surface 17 is inclined with respect to the rotating shaft 13 as shown in FIG. In this case, the gyro output obtained by rotating the gyro unit 11 cannot be regarded as a simple sine waveform. In the case of measurement on the equator, a positive / negative symmetrical waveform is formed around the zero point, and no problem occurs. However, when the measurement is not performed on the equator, the amplitude of the gyro output of the gyro unit 11 differs depending on whether the amplitude is positive or negative, and the ratio increases as the distance from the equator increases, that is, as the latitude increases.
Further, when the gyro unit 11 is rotated 90 ° from the state shown in FIG. 6, the true gyro surface 17 and the rotation axis J of the earth E are vertical, and the rotation felt by the gyro unit 11 is zero.
In the rotation sensed by the gyro unit 11 when the gyro unit 11 is continuously rotated in this state, the rotational angular velocity component of only the rotation component of the earth E is given by the following formula.

Ω = Ω _E · (sin β) · cos (α + δ · sin β) where β is the rotation angle, and when β = 0, the rotation component sensed by the gyro unit 11 is zero. This waveform has an irregular waveform in which the rate of change of the gyro output from the time of δ = 0 near the zero is negligible, and the rate of change becomes maximum where the amplitude becomes maximum. Become.

Therefore, in the conventional method of performing the azimuth measurement by continuously rotating the gyro unit 11, there must be no inclination δ between the true gyro surface 17 and the rotation axis 13.

However, in the azimuth measuring method according to the present invention, this problem is almost avoided by using only the portion where the rotation felt by the gyro unit 11 is near zero. Therefore, the gyro unit 11
No special precision is required for the mounting, and no mechanism for correcting the inclination is required.

As described above, the gyro unit 11 is first rotated once, or the gyro unit 11 is stopped at several points during one rotation, and the gyro output of the gyro unit 11 and the output of the encoder plate 14 are measured. Determine the bearing, then
The gyro unit 11 is stopped so that the sensing axis K is roughly directed in the east-west direction.
The gyro output of the gyro unit 11 and the output of the encoder plate 14 at the rotation stationary position rotated by 0 ° are measured, and by repeating this measurement, it is based on the rotation system included in the conventional optical azimuth measuring device. Problems can be avoided.

Further, according to the signal processing method described above, there is almost no influence of the zero point drift. Further, no special precision is required for mounting the gyro unit 11.

For example, when measuring data on the equator for 10 minutes using an optical gyroscope with a resolution of 0.1 ° / h, it is about ±
The azimuth can be determined with an accuracy of 30 ″, and the obtained accuracy depends on the measurement time and the resolution of the gyro unit 11.

In this embodiment, the output of the encoder plate 14 reads the position of the gyro surface 17 determined from the outer shape of the gyro unit 11. Therefore, it cannot be said that the true position of the gyro surface 17 is read. Therefore, in order to eliminate this error, the optical azimuth measuring device is measured with the measured value obtained by measuring the azimuth in the normal state where the surface plate 10 is below, and the optical azimuth measuring device is moved with the surface plate 10 upward. This error is removed by taking the average of the azimuth part 11 and the measured value obtained by measuring the azimuth in the upside down state. Since the error based on the difference from the true gyro surface 17 is constant in both direction and magnitude, if the error is stored in the signal processing circuit, it can be corrected, and even if it is not considered in the subsequent azimuth measurement. Good.

The above azimuth measuring method has the highest sensitivity because the component of the earth's rotation is largest on the equator, that is, at the point of α = 0. Then, the rotational angular velocity component of the earth that the gyro part 11 feels as it moves away from the equator becomes Ω _E cos α, and the sensitivity becomes poor at high latitudes. For example, at α = 45 °, twice the measurement time is required to obtain the same accuracy as on the equator.

Next, a description will be given of a second embodiment of the azimuth measuring method using the optical azimuth measuring apparatus according to the present invention and an apparatus used for the azimuth measuring method.

As shown in FIG. 7, the gyro surface 17 of the gyro unit 11 is inclined by an angle equal to the latitude α. Then, the rate of sensing the component of the rotation of the earth E becomes the maximum. Therefore, the measurement is always the same as on the equator, and the mounting accuracy of the gyro portion 11 can be further reduced.

Therefore, as shown in FIG. 8, an optical azimuth measuring device is configured. In FIG. 8, reference numeral 18 denotes a housing. The housing 18 is provided with rotation support shafts 19, 19. The axis of the rotation support shaft 19 is in the rotation plane of the encoder plate 14, and the axis is orthogonal to the axis of the rotation shaft 13. The rotating shafts 19 are rotatably attached to the housing 20. The motor 21 is fixed to the side wall of the housing 20.
A gear (not shown) is provided on a rotating shaft 22 of the motor 21, and the gear is meshed with a gear 23 attached to the rotating shaft 19.

The housing 18 is rotated by the motor 21 and the gear 23 of the rotation support shafts 19, 19.
Is rotated around. An encoder 24 is mounted on the rotation support shaft 19 on which the gear 23 is not mounted. The housing 20 is installed on the turntable 30. That rotary table
30 has a rotating shaft 31, and the rotating shaft 31 is oriented in a vertical axis direction. The rotary shaft 31 and the rotary shaft 13 are designed to coincide with each other when the housing 18 is rotated by a certain angle by the motor 21.

The rotary table 30 is rotated by a motor 32,
Reference numeral 33 denotes a gear train as a rotation transmission mechanism between the motor 32 and the rotary table 30. Rotary axis 31 of rotary table 30
, An encoder plate 34 is attached, and the center of the encoder plate 34 coincides with the rotation shaft 31. At the upper part of the turntable 30, an encoder reading unit 35 is provided concentrically with the encoder plate 34. The rotary table 30, the motor 32, and the gear train 33 are installed on a surface plate. The stool 36 is installed in, for example, a transit.

 Next, an azimuth measuring method according to this embodiment will be described.

First, the scale of the encoder plate 14 and the encoder plate
Correlate with 34 scales. For convenience of explanation, it is assumed that the scale of the encoder plate 14 and the scale of the encoder plate 34 are set in the same direction in the initial state of the measurement. Further, it is assumed that the rotating shaft 13 and the rotating shaft 31 are oriented in the vertical axis direction. The encoder reading unit 35 reads the rotation position of the rotation shaft 31, that is, the rotation position of the rotation support shafts 19, 19 around the rotation shaft 31.

Then, the rough azimuth is measured by the azimuth measuring procedure shown in the first embodiment, and the gyro surface 17 is set roughly in the east-west direction (see the state of FIG. 7 (a)). Although it can be performed using the motor 32,
Here, it is assumed that the motor 12 is used for setting.
At this time, the scale of the encoder plate 14 was read, and the rotation support shaft 19,
The motor 32 is driven to rotate the turntable 30 so that 19 is in the east-west direction. Then, the gyro surface 17 is shifted from the initially set east-west direction roughly by the amount of rotation of the turntable 30. Therefore, when the motor 12 is rotated in the opposite direction by the amount of rotation of the rotary table 30, the gyro surface
17 will be roughly east-west.

The gyro surface 17 of the gyro unit 11 is roughly determined by the motor 12.
Since the magnitude of the gyro output with respect to the rotational angular velocity of the gyro unit 11 is already known when setting the distance in the east-west direction, the latitude α of the measurement point can be roughly determined by the amplitude of the sine waveform. In the signal processing circuit, this latitude α
A function that roughly asks for is added.

This latitude α can be obtained as follows.

Gyro output V with respect to the angular velocity Ω _E of rotation of the earth E
(Ω _E ) and the amplitude of the sine waveform actually obtained is V, V = V (Ω _E ) · cos α Therefore, α = cos ⁻¹ (V / V (Ω _E )) Based on the latitude α thus obtained, the motor 21 is driven to rotate the gyro unit 11 from the state shown in FIG. 7 (a) about the rotation support shafts 19 and 19 by an angle corresponding to the latitude α. Then, the gyro surface 17 of the gyro unit 11 is set to the state shown in FIG. 7 (b). The gyro part
The direction in which 11 is rotated about the rotation shafts 19, 19 is already known when a rough direction is determined. Alternatively, it can be understood from the increase and decrease of the gyro output. Its direction is different in the Southern and Northern Hemispheres.

Here, the setting error of the latitude α will be considered.
Assuming that the angle at which the gyro unit 11 is rotated about the rotation shafts 19 by the motor 21 is shifted from the true latitude α by Δα, the amplitude value of the virtual sine wave as the gyro output is slightly reduced. However, even if it deviates from the true latitude α by 5 °, the rate at which the gyro unit 11 feels the component of the rotation of the earth E becomes only about 0.4% smaller. Therefore, it is not necessary to particularly consider the accuracy of the encoder 24. For example, when a pulse motor is used as the motor 21, the encoder 24 itself becomes unnecessary.

By the way, as the measurement point becomes higher in latitude, the amplitude of the sine waveform decreases as described above. Therefore, the accuracy of determining the rough orientation also deteriorates. Since the motor 32 is driven based on the rough azimuth, if the accuracy of the rough azimuth determination is deteriorated, a trouble occurs in the subsequent accurate azimuth measurement, and the data deviated from the linear approximation of the sine waveform. It will be measured using. Therefore, when the amplitude value of the sine waveform is equal to or less than a certain value, that is, when the measurement point is at a high latitude and the rotation axis 13 and the rotation axis 31 are oriented in the vertical axis direction, the azimuth measurement procedure shown in the first embodiment is performed. If it is difficult to set the gyro surface 17 roughly in the east-west direction, measure the rough azimuth, and rotate the gyro unit 11 about the rotating shafts 19, 19 with the motor 21. The gyro unit 11 is lifted to increase the rate of sensing the rotation component of the earth E, and then the motors 12 and 32 are similarly driven to roughly determine the east-west direction.

Alternatively, when the accuracy of determining the rough azimuth deteriorates to some extent, that is, when the amplitude of the sine waveform becomes smaller than a certain value, set it once with the method described above and then reset it using the same method again. Good. In other words, this problem does not occur if the rough azimuth measurement is performed twice.

When the latitude α of the measurement point is roughly known, the data of the latitude α is input using an external input device,
As a result, the gyro unit 11 can be raised. In this case, the rotary shafts 19, 19 are
Is detected.

The gyro surface 17 is set in the state shown in FIG. 7 (b) by the above measurement procedure, and then an accurate azimuth is obtained by the same procedure as the azimuth measurement procedure of the first embodiment.

When a correlation is established between the encoder plate 14 and the encoder plate 34, the azimuth can be displayed using the scale of the encoder plate 34.

According to the optical azimuth measuring apparatus according to the second embodiment,
As described below, the latitude α can be measured. The gyro 11 is set to the state shown in FIG. 7 (b) by the above-described method, and the gyro 11 is rotated by the motor 21. When rotated around 19, the gyro output has a sinusoidal waveform. Therefore, this sine waveform and the rotation axis
The latitude can be measured by the same measurement method as described above based on the relationship with the amount of rotation of 19.

According to the azimuth measuring method using the optical azimuth measuring device according to the present invention, since the azimuth can be measured without continuously rotating the gyro, an error based on continuously rotating the gyro, that is, the error of the gyro, It is possible to remove errors caused by fluctuations in the rotation axis and rotation speed of the rotation axis. In addition, it is possible to remove an error due to a zero point drift of the gyro output and an error based on the inclination between the rotation axis of the gyro unit and the true gyro surface.

Therefore, according to the azimuth measuring method using the optical azimuth measuring device according to the present invention, there is an effect that the advanced manufacturing technology required for the optical azimuth measuring device can be relaxed.

Further, according to the device used in the azimuth measuring method by the optical azimuth measuring device according to the present invention, the azimuth can be accurately measured regardless of the latitude of the measurement point. Further, a latitude measuring function can be added.

[Brief description of the drawings]

1 (a) and 1 (b) are schematic diagrams for explaining the measurement principle of the optical azimuth measuring device according to the first embodiment of the present invention, and FIG. 1 (c) is a graph showing the gyro output. FIG. 2 is a diagram showing a schematic configuration of an optical azimuth measuring device according to the present invention. FIG. 3 is a schematic diagram for explaining an azimuth measuring method by the optical azimuth measuring device according to the present invention. 5 is a sine curve diagram showing the relationship between the gyro output and the encoder output obtained by rotating the gyro unit 11 shown in FIG. 3, and FIG. 5 is the relationship between the gyro output and the encoder output processed by the signal processing circuit. FIG. 6 is a schematic diagram for explaining the influence of the inclination of the true gyro surface and the rotation axis of the gyro portion on the gyro output, and FIGS. 7 (a) and 7 (b) are the figures. Measurement principle of optical azimuth measuring device according to a second embodiment of the invention Schematically explaining to view, FIG. 8 is a diagram showing a schematic configuration of an optical azimuth measuring device according to the second embodiment. 11 ... Gyro part, 12 ... Motor, 13 ... Rotating axis 14 ... Encoder plate, 15 ... Encoder reading part 17 ... Gyro surface, 19 ... Rotating support shaft 21 ... Motor, 24 ... Encoder, 30 ... rotary table 32 ... motor, 31 ... rotary axis, 34 encoder plate 35 ... encoder reading section K ... sensing axis α ... latitude

Claims (3)

(57) [Claims] 1. A gyro surface is made to stand still so that the rotational angular velocity of the earth's rotation sensed by the gyro unit of the optical azimuth measuring device becomes substantially zero, and a gyro output at this stationary position and a stationary position relative to a reference position are set. Next, the gyro unit is rotated by 180 ° from its stationary position to stand still, and the relationship between the 180 ° rotational stationary position of the gyro unit and the gyro output at this 180 ° rotational stationary position is determined. This operation is repeated many times, and a plurality of relational values obtained in this way are obtained to approximate a straight line, and the azimuth is obtained by the rotation angle at which the output of the gyro part of this straight line becomes zero. Direction measurement method using a measuring device. A rotating shaft for rotating the gyro, a rotating shaft for rotating the gyro including the rotating shaft in a plane perpendicular to the rotating shaft, and a rotating shaft for rotating the gyro at a predetermined rotation position of the rotating shaft. The gyro unit has a rotation axis that is coaxial with the rotation axis of the gyro unit, and the gyro surface is adjusted so that the rotation angular velocity of the rotation of the earth felt by the gyro unit increases to correct a decrease in the gyro output due to an increase in latitude. An apparatus for use in an azimuth measuring method using an optical azimuth measuring apparatus, wherein the azimuth is measured by rotating the azimuth about the rotation support shaft. 3. An apparatus for use in an azimuth measuring method using an optical azimuth measuring apparatus according to claim 2, wherein the amount of rotation of the rotation support shaft is detected to measure the latitude.